1. Field of the Invention
The present invention relates to a cooling arrangement for a gun barrel and more particularly for a gun barrel of a combat tank.
When projectiles are fired, the gun barrel of a combat tank is heated by the combusted fuel of the projectile. The heated barrel constitutes a clearly recognizable object for thermal imaging devices. Specifically, the infrared (IR) signature of a combat tank whose gun barrel has been heated from firing is particularly distinct to these thermal imaging devices. Therefore, to avoid detection by the thermal imaging devices it is desirable to cool the gun barrel surface to ambient temperature as quickly as possible after firing, or to prevent, from the start, the gun barrel surface temperature from rising too much.
A further heating problem encountered with gun barrels results when the gun barrel is subjected to the radiation of the sun, and is therefore only heated from one side. This radiation heating from one side causes the barrel to bend or deform to the extent that there develops a deviation between the optical axes of the aiming device and the actual direction of firing. To prevent this deformation of the barrel, and the resulting deviation between the aiming device and the direction of firing, the barrel should be substantially shielded against exposure to the sun. In addition, if there is any remaining heat reaching the body of the barrel, this heat must be distributed uniformly over the circumference of the barrel.
Particular difficulties result in solving these problems because of the actual function and operation of a gun barrel. For example, all devices fastened to the barrel must be able to withstand the great forces generated during recoil of the barrel. The recoil acceleration force for the 120 mm smooth barrel cannon employed by the Leopard 2 tank is of the order of magnitude of 300 g with the barrel recoiling about 0.3 m. Over this recoiling length, the barrel must be freely movable within the guides provided for this purpose. Moreover, one type of device that is normally mounted on the gun barrel is a smoke extraction device. Conventionally, the smoke extraction device is pushed in the manner of a sleeve over the part of the barrel that projects freely from the turret. If a cooling device is utilized to overcome other problems of the barrel, the smoke extraction device constitutes an impediment which must be overcome or bridged. If possible, the smoke gas extraction device should be included in the components being cooled.
2. Discussion of the Prior Art:
A gun barrel for a combat tank which is equipped with insulation tubes made of glass fiber reinforced plastic is known. This known arrangement reduces the temperature of the outer surface of the gun barrel to some extent and thus reduces the IR heat radiation when the barrel is hot from firing. If the gun barrel is exposed to the sun, the glass fiber reinforced plastic insulation tubes shield the gun barrel against some of the irradiated heat. However, the thermal insulation provided by the glass fiber reinforced plastic tubes is neither sufficient to protect the barrel against IR detection when it is hot from firing, nor from deformation or bending of the barrel when it is exposed to the radiation of the sun. Additionally, the problems encountered in mechanically fastening the glass fiber reinforced plastic tube to the gun barrel have not yet been completely solved.